Improvement in concrete pavements



UNITED STATES PATENT OFFICE.

AARON VAN CAMP, OF WASHINGTON, DISTRICT OF COLUMBIA.

IMPROVEMENT IN CONCRETE PAVEMENTS.

Specification forming part of Letters Patent No. 174,648, dated March 14, 1876; application filed.

. August 27, 1675.

To all tvhom it may concern:

Be it known that I, AARON VAN CAMP, of Washington city, in the county of \Vas'hington and D strict of Columbia, have invented certain new and useful Improvements in Concrete Pavements for Streets and Sidewalks; and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to which it appertains to make and use the same.

I take crushed and pulverized rock, sixty per centum ot the finer pulverized portion, and forty per cent. of the coarser. The crushing and pulverizing process should be continued until the even or naturally smooth surface of the stone is entirely destroyed. The object of crushing and pulverizing the rock is to obtain sharp angles and rough surfaces. I use the blue limestone; but it is evident that any hard rock, bowlder, or gravel,when crushed and pulverized, will answer my purpose. The

rock thus crushed and pulverized I subject to heat, so as to expel the moisture. I then add dead-oil, crude petroleum, or the residuum of petroleum until the rock becomes perfectly saturated. While thus heated I add about twenty per cent. of natural asphlaltum,

Cuban, Trinidad, or California, that has been previously dissolved by crude petroleum, or

forniTaj p reviously dissolved to a pitch by--' crude petroleum or the residuum of petroleum, substantially as described, and for the purpose set forth.

In testimony that I claim the foregoing as my. own I affix my signature in presence of two witnesses.

AARON VAN CAMP.

'Witnesses:

H. D. ()LER, THOMAS J. SHEA. 

